Process for removing acetylene from a C2 -stream

Abstract

Acetylene is removed from a crude C 2 -stream by scrubbing with an absorbent in an absorption column, a liquid, substantially acetylene-free C 2 -stream being fed into the absorption column between the feed points for the crude C 2 -stream and for the absorbent.

What is claimed is: 
     
       1. In a process for removing acetylene from a crude C 2  -stream by introducing the same into an absorption column and therein introducing an absorbent at a point above the point at which said crude C 2  -stream is introduced and therein absorbing acetylene in said absorbent, the improvement wherein a stream consisting of liquid C 2  which is substantially acetylene free is fed into the absorption column between the feed points of the crude C 2  -stream and for the absorbent. 
     
     
       2. A process according to claim 1 wherein the liquid substantially acetylene free C 2  -stream is an ethylene, ethane or ethylene/ethane stream. 
     
     
       3. A process according to claim 1 wherein said liquid substantially acetylene free C 2  -stream is substantially pure ethylene. 
     
     
       4. A process according to claim 1 wherein said liquid substantially acetylene free C 2  -stream is introduced into said absorption in an amount of 1 to 4 percent by weight upon the weight of said crude C 2  -stream. 
     
     
       5. A process according to claim 1 wherein said liquid substantially acetylene free C 2  -stream is introduced into said absorption column in an amount of 1.3-3.3 percent by weight based upon the weight of said crude C 2  -stream. 
     
     
       6. A process according to claim 1 wherein said liquid substantially acetylene-free C 2  -stream is introduced into said absorption column in an amount of 1.5-2.5 percent by weight based upon the weight of said crude C 2  -stream. 
     
     
       7. A process according to claim 1 wherein at the top of said absorption column there is withdrawn a C 2  -stream and a portion of said C 2  -stream is refluxed back to the absorption column but the rate of reflux is reduced by at least the amount of C 2  -stream fed into said absorption column between the feed points for the crude C 2  -stream and for the absorbent. 
     
     
       8. A process according to claim 1 wherein the process is carried out without refluxing C 2  -stream removed from the top of the absorption column. 
     
     
       9. A process according to claim 1 wherein said liquid substantially acetylene-free C 2  -stream is one in which, in the subsequent working up process of the top product of the absorption column, is under a higher pressure than the pressure in the absorption column. 
     
     
       10. A process according to claim 1 wherein the absorbent is an N-alkyl-pyrrolidone. 
     
     
       11. A process according to claim 1 wherein said absorbent is N-methyl-2-pyrrolidone. 
     
     
       12. A process according to claim 1 wherein said absorbent is a dialkylformamide. 
     
     
       13. A process according to claim 1 wherein said absorbent is dimethylformamide or diethylformamide. 
     
     
       14. A process according to claim 1 wherein said absorbent is a lower aliphatic ketone. 
     
     
       15. A process according to claim 1 wherein said absorbent is acetone or methylethyl ketone.